Aims: Knowledge of invasive alien plant (IAP) ecology and plant community succession (synphytosociology) is crucial for successful restoration and prevention of (re)invasions; nevertheless, these two fields are rarely combined. Our case study aims to demonstrate how they can be integrated, by analysing the variation of IAP distribution within biogeographic territories, identifying the potential native plant communities and the ecological conditions that favour (or prevent) each IAP. Location: Southern Portugal. Methods: Several native plant indicators and nine selected IAPs were surveyed in 60 1-km2 sampling plots across the four biogeographic sectors of the study area. The native plant indicators were then used to identify the vegetation series in which IAPs occurred. Ecological requirements favouring the establishment of each IAP were inferred based on expert knowledge and on the characteristics of published vegetation series and bioclimatic data. Results: Littoral areas were more invaded, particularly those with sand dune habitats, which are highly dynamic and exposed to disturbance. The most frequent IAPs were Acacia dealbata, Arundo donax, Acacia longifolia and Opuntia ficus-indica. Riparian vegetation series were the most invaded, especially ash woodlands and willow galleries, as well as the littoral psammophilous cork oak and maritime turbinate juniper series. The most adequate native species to recover each of these invaded communities varies, and examples are provided for each situation. Conclusions: Integrating knowledge about IAP ecological requirements and the dynamics of native vegetation series can help practitioners select native plants that are more likely to function as efficient natural barriers to (re)invasion, predict areas more prone to invasion by IAPs and establish management priorities.
